Interface TreeModel

JTree and its related classes make extensive use of
TreePaths for indentifying nodes in the TreeModel.
If a TreeModel returns the same object, as compared by
equals, at two different indices under the same parent
than the resulting TreePath objects will be considered equal
as well. Some implementations may assume that if two
TreePaths are equal, they identify the same node. If this
condition is not met, painting problems and other oddities may result.
In other words, if getChild for a given parent returns
the same Object (as determined by equals) problems may
result, and it is recommended you avoid doing this.

Similarly JTree and its related classes place
TreePaths in Maps. As such if
a node is requested twice, the return values must be equal
(using the equals method) and have the same
hashCode.

For further information on tree models,
including an example of a custom implementation,
see How to Use Trees
in The Java Tutorial.

Method Detail

getRoot

getChild

Returns the child of parent at index index
in the parent's
child array. parent must be a node previously obtained
from this data source. This should not return null
if index
is a valid index for parent (that is index >= 0 &&
index < getChildCount(parent)).

isLeaf

Returns true if node is a leaf.
It is possible for this method to return false
even if node has no children.
A directory in a filesystem, for example,
may contain no files; the node representing
the directory is not a leaf, but it also has no children.